Here is the engine as it was received by my good friend Adrian Duncan from Canada. This engine is a rather rare beast as neither Adrian nor I could find any real information on it. Despite looking not too bad the engine is actually in a very sad state of affairs. there is excessive play in the crankshaft plain bearing, con-rod was flogged out at both ends, loose gudgeon pin had also caused damage to the cylinder bore and wouldn't actually turn over without making some very not good sounds and clunks.


As with every job that comes in we always start with a complete dismantle of the subject engine and appraisal for what we've got ourselves in for. In this case it was a not so obvious total restoration from the brink of the rubbish bin. The engine had obviously been repaired previously and it must have been substantial as the case showed signs of being weld repaired. The good news was that whoever had carried out that part of the job was good at doing so.

 Photos below show the main crankcase, back plate and cylinder head after cleaning and refinishing to as close to "like new" as possible.

Next we made a new needle valve assembly consisting of a new fuel jet, new needle carrier and a new fuel mixture needle. We were able to reuse the original adjusting knob as we were able to successfully remove it from the original threaded mixture needle. Photos below show progress.

At the above stage we also resized the crankshaft plain bearing in the case and made a new crankshaft to fit. While making the crank we also took the liberty of correcting a few design flaws by resizing the intake port drilling in the shaft to strengthen the somewhat undersized 8mm shaft to increase the strength of the shaft and then redesigned the intake port window to allow the maximum amount of intake duration to give a half pie decent fuel intake.

Below photos show the new crank and prop driver fitted up to the case assembly and the new gaskets.

Next came the cylinder liner and piston. the liner was cleaned and re-lapped to get the correct tapper back into it and to, well, make it round again. We then made a new piston and contra piston, with gudgeon and con-rod to complete the cylinder assembly ready to reassemble to the rest of the engine.


Once all the internal parts were made and made ready we final assembled the engine ready for the big test run. Along the way we discovered that the cylinder head bolts had been butchered beyond redemption so we re-drilled and re-tapped to accommodate M 2.5 high tensile cap screw bolts.

Below photos show the finished engine final assembled and ready to add fuel.

While this engine does suffer from some fairly serious design flaws it is a very nice looking engine and I do feel a custom build project coming on just to satisfy my curiosity to see just what this engine could have been like had a bit more thought been put into it in the early design stage to end up with a power unit that would have been far more powerful and therefore more useful to the modeler of the day. Watch this space.........